The present invention relates to mixtures of substances containing bisphenol A as well as two processes for the preparation thereof and their use for preparing polymer materials.
Bis(4-hydroxyaryl)alkanes, in the following called bisphenols, are important as starting materials or as intermediates for preparing a number of commercial products. Bisphenols can be prepared by the condensation of phenols and carbonyl compounds. Substituted phenols or unsubstituted phenol may be used.
The condensation product from the reaction between phenol and acetone, 2,2-bis(4 hydroxyphenyl)propane (bisphenol A, BPA, p,p-BPA) is of particular industrial importance. BPA is used as a starting material for preparing various types of polymer materials such as, for example, polyarylates, polyetherimides, polysulfones and modified phenol/formaldehyde resins. Preferred areas of application are the preparation of epoxy resins and polycarbonates.
Processes for preparing bisphenols by acid-catalysed reaction of phenols with carbonyl compounds are known, for example from U.S. Pat. No. 2,775,620 and from EP-A-0 342 758.
Bisphenols of general structure can be prepared by processes which are analogous to the preparation of BPA.
Phenol resins are artificial resins which are obtained by the condensation of phenols (or bisphenol A) with aldehydes, in particular formaldehyde, by derivatisation of the condensates resulting therefrom or by the addition of phenols to unsaturated compounds such as e.g. acetylene, terpenes or natural resins.
Compounds called epoxide resins are either oligomeric compounds with more than one epoxide group per mole, which are used to prepare thermoset materials, or else the corresponding thermoset materials themselves. The conversion of epoxide resins is achieved via polyaddition reactions with suitable hardeners or by polymerisation via the epoxide group. More than 90% of current world-wide production takes place by reacting bisphenol A with epichlorhydrin.
The term formaldehyde resins includes the industrially very important urea, melamine, phenol and, in a wider sense, furan resins which are prepared by condensation of formaldehyde with urea, melamine, phenol or phenols (including bisphenol A) and furfuryl alcohol as monomers which contain NH or OH groups.
Polymer materials such as, for example, phenol resins, epoxide resins or formaldehyde resins may be prepared using bisphenol A as a raw material. The disadvantage of this is that bisphenol A in the pure form is expensive, and in addition it is disadvantageous that the properties of the polymer materials mentioned are not optimal when they are prepared using pure bisphenol A as a raw material.
Thus, the present invention is based on the object of providing a process for preparing polymer materials, for example phenol resins, epoxide resins or formaldehyde resins, which does not have the disadvantages of the prior art mentioned above.
The object according to the invention is the use of a mixture of substances containing bisphenol A and secondary products which are produced during the production of bisphenol A to prepare polymer materials such as, for example, phenol resins, epoxide resins or formaldehyde resins.
The present invention therefore provides a mixture of substances containing bisphenol A and secondary products which are produced during the production of bisphenol A.